Q: A patient receives an electric shock of $$0.5 A $$for $$0.2 s. If $$the voltage across the body is $$120 V$$, what is the total energy delivered?

$$E = V I t = 120 \times 0.5 \times 0.2 = 12 J$$

Q: A loop of wire is placed in a region where the magnetic field increases from $$0 to$$ $$2 T in$$ $$0.5 s. If $$the area of the loop is $$0.1 m$^2$$, what is the average induced emf?

$$\mathcal{E} = \frac{\Delta \Phi}{\Delta t} = \frac{2 \times 0.1}{0.5} = 0.4 V$$

Question 1

Which of the following best describes Coulomb’s law?

Accepted Answer

It states that the force between two charges is proportional to the product of their charges and inversely proportional to the square of the distance between them.

Question 2

A point charge $$q is $$placed at the center of a spherical conducting shell of radius $$R. $$What is the electric field at a distance $$r$$ from the center, where $$r \u003c R$$?

Accepted Answer

$$E = \frac{1}{4\pi\$$varepsilon_0$$} \frac{q}{r^2$}$$

Question 3

Which of the following is a correct application of Gauss’s law for a uniformly charged infinite plane?

Accepted Answer

$$E = \frac{\sigma}{2\$$varepsilon_0$$}$$

Question 4

A capacitor is charged to a voltage $$V$$ and then disconnected from the battery. If the plates are pulled apart to double their original separation, what happens to the stored energy?

Accepted Answer

The energy doubles.

Question 5

Which equation represents Ampere’s law in integral form?

Accepted Answer

$$\oint \vec{B} \cdot d\vec{l} = \mu_0$ I_{enc}$$

Question 6

A long straight wire carries a current $$I. $$What is the magnetic field at a distance $$r$$ from the wire?

Accepted Answer

$$B = \frac{\mu_0$ I}{2\pi r}$$

Question 7

A resistor, capacitor, and inductor are connected in series to an AC source. Which equation gives the impedance $$Z of $$the circuit?

Accepted Answer

$$Z = \sqrt{R^2$ + (\omega L - \frac{1}{\omega C})^2$}$$

Question 8

A patient receives an electric shock of $$0.5 A $$for $$0.2 s. If $$the voltage across the body is $$120 V$$, what is the total energy delivered?

Accepted Answer

$$E = V I t = 120 	imes 0.5 	imes 0.2 = 12 J$$

Question 9

Which of the following best describes electromagnetic induction?

Accepted Answer

A changing magnetic field produces an electric field.

Question 10

A loop of wire is placed in a region where the magnetic field increases from $$0 to$$ $$2 T in$$ $$0.5 s. If $$the area of the loop is $$0.1 m$^2$$, what is the average induced emf?

Accepted Answer

$$\mathcal{E} = \frac{\Delta \Phi}{\Delta t} = \frac{2 	imes 0.1}{0.5} = 0.4 V$$

Question 11

Which equation describes the speed of light in vacuum?

Accepted Answer

$$c = \frac{1}{\sqrt{\mu_0$ \$$varepsilon_0$$}}$$

Question 12

A parallel plate capacitor with plate area $$A$$ and separation $$d is $$filled with a dielectric of constant $$\kappa. $$What is the capacitance?

Accepted Answer

$$C = \kappa \$$varepsilon_0$$ \frac{A}{d}$$

Question 13

A circuit contains a battery of voltage $$V$$, a resistor $$R$$, and a capacitor $$C in $$series. What is the charge on the capacitor after a long time?

Accepted Answer

$$Q = C V$$

Question 14

Which of the following is a correct statement of Faraday’s law?

Accepted Answer

$$\mathcal{E} = -\frac{d\Phi_B}{dt}$$

Question 15

A hospital MRI machine uses a magnetic field of $$3 T. If a $$patient’s body contains a loop of area $$0.05 m$^2$$ and the field changes by $$0.1 T in$$ $$0.2 s$$, what is the induced emf?

Accepted Answer

$$\mathcal{E} = \frac{\Delta \Phi}{\Delta t} = \frac{0.1 	imes 0.05}{0.2} = 0.025 V$$

Question 16

Which of the following best describes the direction of the induced current according to Lenz’s law?

Accepted Answer

It opposes the change in magnetic flux.

Question 17

A real-world application: In a pacemaker, a capacitor stores energy to deliver a pulse. If the capacitor has $$C = 10 \muF $$and is charged to $$V = 2 V$$, what is the energy stored?

Accepted Answer

$$U = \frac{1}{2} C V^2$ = \frac{1}{2} 	imes 10 	imes 10$$^{-6}$$ 	imes 2^2$ = 20 	imes 10$$^{-6}$$ J

Question 18

A lightning bolt transfers $$10^9 C of $$charge in $$0.01 s. $$What is the average current?

Accepted Answer

$$I = \frac{Q}{t} = \frac{10^9$}{0.01} = 10$$^{11}$$ A

Question 19

Which equation gives the power dissipated in a resistor in a DC circuit?

Accepted Answer

$$P = I^2$ R$$

PHYS 262: General Physics II – Electricity and Magnetism (Syllabus Overview and Study Guide)

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